The present invention generally relates to fabrication methods and resulting structures for magnetoresistive random access memory (MRAM). More specifically, the present invention relates to a self-aligned ion beam etch (IBE) sputter mask for MRAM.
MRAM is a solid state, non-volatile memory that uses magnetoresistance to store information. MRAM includes an electrically connected array of magnetoresistive memory elements, referred to as magnetic tunnel junctions (MTJs). Each MTJ includes two magnetic layers separated by an insulator layer. Electrons can tunnel from one ferromagnetic layer to the other when the insulating layer is thin enough.
An applied write current can be used to individually switch the magnetization directions of the magnetic layers. If the magnetization directions are in a parallel orientation, electrons are more likely to tunnel through the insulator layer than when in an antiparallel orientation. Consequently, such a junction can be switched between two states of electrical resistance, one with low and one with very high resistance.